1. Field of the Invention
The invention relates to a crane with a boom. The invention can be used anywhere where parts of the travel track of chassis that run on rails are movable, but are supposed to form a total, united travel track in the operating position, such as, for example, in crane construction for ship unloaders, container loading bridges, and other cranes with folding booms, for the travel track of the trolley power feed lines, but also for the power feed of stackers and other movable machines or devices that run on rails.
The crane according to the invention has the advantage that the running tracks of line cable carriers have a significantly lesser gap at the connection point between their fixed part and their movable part, and therefore greatly reduce the impact in the travel track resulting from the gap, when passing over the join, as well as the wear for the adjacent parts, such as wheels, bearings, and the running track itself.
2. The Prior Art
Cranes with booms are known. For example, in German Patent No. DE 197 13 489 A1, a loading bridge and a method for loading/unloading goods, particularly at ship docks, are described, with a portal-like base frame of at least four supports resting at least approximately vertically on a chassis, at least one beam, consisting of a fixed bridge beam extended beyond the portal on the land side, and a pivoting folded boom that is held in its horizontal position by means of pull rods mounted on a pylon in articulated manner. Trolleys that can move on travel tracks of the bridge beam and the boom are provided, which transport containers.
In order for the trolleys that move along their travel track on the crane and boom to be supplied with power, cable carriers move along a running track disposed below a beam, by means of which carriers a line or a line bundle can be moved out parallel to the boom. At all movable transitions of the crane, the running track has joins, which the cable carrier must cross with its wheels. Depending on the temperature difference, material, and design of the crane, these gaps can be several millimeters wide under disadvantageous conditions, and this results in significant stress on the bearings of the cable carrier, brings about vibrations of the crane, and results in great wear of both the running track of the cable carrier and of the bearings of the same.
This problem also occurs in the case of other movable chassis that run on rails, as described initially. In German Patent No. DE 197 53 169 C2, a device for suspension of a rail, particularly a rail in the shape of a hollow profile, open towards the bottom, of a suspended crane is described, with a lower metal beam that is attached to a chassis and on which a flexible element is supported. This element is situated between the lower metal beam and an upper metal beam that is parallel to the former, in the unstressed state, on which latter beam a tension element is supported, so that displaceablity between various elements exists.
From German Patent No. DE 197 08 747 A1, the suspension of a rail is known, and at least one additional element held at bias by the tension element is provided, to transfer pressure forces between the rail and the chassis.
These solutions are not suitable for solving the problem mentioned above.
In German Patent No. DE-OS 41 20 284 A1, a blocking and locking device for crane tracks is described, in which, after transport rails that are movable crosswise to one another have been aligned, the ends of the transport rails can be locked into one another after alignment, and, at the same time, barriers that are present at the ends are released.
The solution according to the invention provides driving the coupling and device for releasing the barrier with independent motors. This solution is not suitable for connecting running tracks for cable carriers, because of its complexity.
U.S. Pat. No. 1,553,439 describes a mechanism for unlocking crane tracks, which has an extraordinary number of parts and is therefore complicated and expensive to produce. This mechanism is not suitable for structuring a running track for the cable carrier of a crane, in uncomplicated manner, in such a way that they are only a slight distance apart at their transition points.